The Research Resource Core A will perform quantitative single-cell assays and assist the investigators of the Physical Science - Oncology Center (PS-OC) to perform the research proposed in Projects 1, 2 and 3. This core facility addresses the need for new technologies that enable the monitoring ofthe functional response of primary tumor cells in their native context. To achieve this, we will rely on recent developments in flow cj/tometry that multiplex measurements of phenotypic variability, functional state of activation and/or the response to drugs in heterogeneous populations of cells. Specifically, this core will focus on measuring phospho-profiles of drugsensitive pathways (e.g. EGFR), downstream signaling cascades (e.g. AKT and MAPK pathways), cell-cycle phases, and apoptotic response at the single cell level. Special emphasis will be given to quantification of parameters for the djmamics of tumor cell proliferation and death (e.g. during drug treatment with varying concentration). This core will contribute to the PS-OC by providing quantitative measurements that parameterize